DESCRIPTION:(adapted from applicant's abstract) Pain-related disorders present a significant economic and clinical problem. The development of treatments is hindered by a lack of information regarding the basic brain mechanisms that support sensory aspects of pain experience. Functional imaging studies provide powerful tools for addressing this issue in human subjects. The investigators have identified activity within a highly distributed network of brain regions that may contribute to sensory-discriminative pain processes. The relationship of this activation to awareness of specific features of pain such as intensity and location, however, remains poorly understood. These perceived sensory aspects of pain can be modulated by cognitive interpretation and expectations about the nature of the stimulus. The brain mechanisms underlying this modulation remain unknown. We propose a series of psychophysical and functional imaging studies to test the hypotheses that 1) parieto-frontal mechanisms are engaged during awareness of the location and intensity of painful stimuli; and 2) that activation within these areas can be modulated by cognitive processes related to expectations about the nature of painful stimuli. These studies will enhance our knowledge of brain mechanisms underlying the pain experience and will provide new directions for the behavioral management of pain.